Electric switch



March 25,- 1947. D, w JOHNSON Re. 22,856

I ELECTRIC swITcH Original Filed April 12, 1941 2 Sheets-Sheet l DAVIDw. JOHNSON 5y 711:5 al'arneiy March 25, 1947. D w JOHNSON Re. 22,856

ELECTRIC SWITCH Original Filed April l2, 1941 2 Sheets-Sheet 2 nven forDAVID W. JOHNSON by his a-Zrneys of Fig. 5, with the switch Reissues]Mar. 25, 1947 ELECTRIC SWITCH lDavid W. Johnson, New Britain, Conn.,assignor to The Arrow-Hart & Hegeman Electric Co., Hartford, Conn., acorporation of Connecticut Original No. 2,286,965, dated `lune 16, 1942,Serial No. 388,333, April 12, 1941. Application for reissue December 10,1946, Serial No. 715,165

15 Claims. l

This invention relates to electric switches. More particularly itrelates to manually-operable electric switches having provision forautomatic operation upon the occurrence of an overload current.

It is an object of my invention to'provide improved switch structureprovided with thermallyresponsive means for causing separation of theswitch contacts on the occurrence of an overload.

Another object of the invention is to provide in a switch of the abovetype improved means for adjusting the setting of the overload responsivemeans.

Another object of the invention is to provide In a switch of the abovetype improved means for causing opening of the contacts automaticallyand improved means for adjusting the overload characteristics by varyingthe position of the operating mechanism with respect to thethermally-responsive parts.

Other objects and advantages of my invention will become apparent as itis described in connection with the accompanying drawings.

In the drawings- Fig. 1 is a longitudinal section view of the inventiontaken substantially along the line I-I parts in manually openedposition;

Fig. 2 is a longitudinal section view, partly broken away, circuitposition;

Fig. 3 is a side elevation view, partly in section, showing the switchparts in the position they occupy after automatic operation;

Fig. 4 is a longitudinal section view taken along line 4-4 of Fig. 5,with the parts in manuallyopened position;

Fig. 5 is a plan view of the invention;

Fig. 6 is a transverse section view taken along line 6-6 of Fig. 5,

Referring to the drawings, the parts of the switch are mounted within arectangular insulating block or base I0 that is hollowed out from thebottom to form communicating cavities for the switch parts.

Adjacent the sides of the base are cavities in which movemutually-insulated contact members 44 and I6 made from thin strips ofspringy highly-conductive metal. One end of each spring showing theswitch parts in closed contact is anchored in position by a hollowrivet,

such as 56, which extends through the top of the base. The other ends ofthe contacts 44 and 46 are provided with contact buttons c and 6c whichengage with stationary contact buttons 52e 2 and 54e on the bottom endsof hollow rivets 52 and 54 that extend through the top of the base Illat the opposite end from the rivets 5|). Screw bolts 50s, 5I, 52s and54s thread intoeach of the -hollow rivets 50, 52, 54. The screws 56s,52s and oted at a central point about a xed pivot I6 whichA is mountedin slots I8 in a central position in the side walls of the base cavity.On the bottom or inner end of the operating member I2 there is ahook-like formation around which is looped one end of a coiled tensionspring 20. The other end of this coil spring is secured to the centralportion of a U-shaped oscillatory switching member 22. The switchingmember 22 preferably is stamped from sheet metal and provided withbifurcated ends. The bifurcations 22a extend through a pair ofclosely-spaced apertures in a flat adjustment bar 26 straddling andpivoting about the narrow portion 26h of the plate between theapertures. The parts are proportioned and positioned so that as thehandle member |12 is rocked, its lower end will pass over the pivotalaxis of the switching member 22 carrying with it the line of action ofthe spring 20 whereby the member 22 Iis moved from a posiiton (Fig. 2)wherein its transverse portion abuts a vertical wall of the casing toanother position (Fig 1) wherein it stands relatively vertically.

Pivotally mounted upon one leg of the member 22 is a tripping orlatching member 3U which is stamped from sheet metal into the angularshape as illustrated. The member 3U .is pivotally mounted on member 22by a pin 28l passing through its central portion and through anenlargement upon one side edge of one of the legs of the member 22.'I'he upper end of the member 36 has an abutment iingerz turned out atright angles to the plane of the member in position to engage with andabut against one end of a bimetallic thermally-responsive member 34. Theother end of the member 36 has a foot portion 3B bent at right angles tothe plane of the main portion of the member 36. The plane of the footportion 38 is substantially parallel to and overlies the plane of theadjustment bar 26 in the open circuit positions of the switch parts, asillustrated in Figs. 1, 3 and 4.

' For the purpose of operating the movable switch 3contactsuandll,abarotinsulatingmaterial lliispositionedinaverticalslotuintheinsulating base and has its lower edgeresting upon the upper surface of the foot portion Il oi! the member 26,so that as the foot portion 22 moves up and down. it will cause similarvertical movement of the insulating bar I0.

ByreterringtoFig.l.itwillbenotedthat with the handle member i2 in theposition there shown. the ei'i'ort of the switch spring is to move theswitching member 22 in a clockwise direction so as to hold it in-theposition shown. In that position, the abutment 32 on the member 26 isdisengaged from the end ofthe thermal member so that the force of thespring contacts 44 and 66 exerted upon the insulatingbar 46 and throughit on the foot portion 38 of the member 30 causes the member 26 to restits toot portion' upon the upper surface of the adjustment plate 26 withthe xed and movable contacts disengaged. If, now, the operating memberis moved about its pivot I6 to the position of Fig. 2, the line ofaction oi the switch spring will'be moved across the pivotal axis of theswitch member 22, causing that member to move counter-clockwise to theposition shown in Fig; 2. 'I'his movement will cause the pivotalconnection 28 between the member 36 and the operating member 22 to moveto the left from the position of Fig. l to the position of Fig, 2.- Suchmovement causes the abutment 32 to engage the end of the bimetallicmember 3l and thereafter causes the member 30 to pivot about its pivotalconnection 28 with the switchy member 22, in turn causing clockwisemovement of the member 30, raising the foot portion 3B thereof to theposition of Fig. 2 and at the same time moving the insulating bar 40upwardly. The upward movement of the insulating bar carries the exiblecontact members 44 and 46 upwardly, engaging the contact buttons on theends thereof with the stationary contact buttons.

For the purpose of influencing the bimetal 3l, there is provideddirectly above the bimetal a heating coil 60, which may be housed withinan insulating shield 62 to conserve its heat and direct the heat againstthe bmetal. The coil 60 is connected with the bimetal by having one endof the coil secured in position by the screw 5l that threads into thehollow rivet 56, The other end of the coil 60 is secured by a screw 68Vto a conductive bar extending transversely of the casing. A securingbolt I2 passes throughthe top of the casing into the bar 1li to secureit in position. At the opposite side of the casing from the attachmentbolt or screw 68 a terminal screw 14 threads into the end of theconductive bar 16.

In connecting the switch to power lines, one wire of the power lines isattached beneath the head of the securing screws 54s, while the otherpower line is connected beneath the head of the securing screw 52s. Thewires of the circuit to be controlled are connected to the terminalscrews 56s and 1I.

When the switch is in closed circuit position,

the current from one line enters through terminal 5l and passes throughthe movable contact 46 to the hollow rivet and terminal screw 50s andthe circuit. The current from the other line enters through terminal 52and passes through the movable contact 44 to the hollow rivet 66,heating coil 60, transverse conductive bar 16 to the terminal screw Iland the circuit.

Upon the occurrence of an overload, heat willbegeneratedinthecoil66,causingthebimetal member ll to flex upwardly,disengaging its' end from the abutment 22 on themember lll. Theresilience of movable contacts, which tendnormally to separate from thexed contacts, exerts a force upon the insulating bar 40 and through iton the toot of the member 20. This force is restrained while the switchparts are in closed circuit positiondue to the abutment 32 engaging theend of the bimetal member 2l. However, when the abutment I2 is free fromengagement with the end of the bimetal 3l, the member 26 can move in acounterclockwise direction, permitting the movable contacts to movedownwardly and disengage from the nxed contacts.

In order to adjust the relative position of the abutment 22 to the endof the bimetal 3|, the adjustment bar 26 is mounted upon an adjustmentbolt` 60 `which passes through the casing irom top to bottom. The lowerend of the adjustment bolt is screw threaded and takes into a screwthreaded aperture in the adjustment plate 26. By this means, rotation ofthe adjustment bolt 60 will cause the adjustment plate 26 to move up anddown along the axis of the adjustment bolt, Since the contact movingparts of the switch mechanism are all supported by the adjustment plate26, it will move up or down as a unit as adjustment is made. Thus, therelative position of the abutment 32 to the end of the bimetal 34 may bevaried by bodily movement of the switching mechanism as a whole. By thismeans, adjustment may be made of the device without imposing any stressor strain upon the bimetal member and Without varying its initial setorits inherent characteristic set. It is, therefore, possible to adjustthe device very accurately and the device will operate according to itsadjustment in a very sharp, distinct and regular manner. The device-alsooperates more accurately and satisfactorily because the bimetal memberdoes not carry the main line current, nor any substantial strain.

From the foregoing, it will be observed that I have provided a novelconstruction of thermallyresponsive, automatically and manually operableswitch mechanism having few and simple parts which are easilymanufactured and assembled and which operate in a very accurate andreliable manner. I have furthermore provided a novel means foradjustment which can be operated without moving the thermally responsiveelementV but by moving the switch mechanism instead.

Many modifications of the invention will occur to those skilled in theart. Therefore, I do not limit it to the specific embodiment illustratedand described.

What I claim is:

i. In an electric switch, a manually operable operating mechanismincluding an over-center spring and a manually operable lever to movesaid spring over-center both into and from closed-circuit position,separable contacts caused to engage and disengage by said mechanism,means operable on occurrence of an overload and employing the stress ofsaid spring to cause separation of said contacts, said overload meansincluding a member responsive to overload conditions, and means toadjust the overload setting of the switch by moving said operatingmechanism relatively to said overload responsive member without movingthe latter. Y

2. In an electric switch, a manually operable operating mechanism.separable contacts engageable `and disengageabie by said mechanism,oversasso load operating means including a V bimetallic member holdingsaid switch in closed-circuit condition, said bl-metallic member movingin response to overload condition to release and to cause separation oisaid contacts, and means to move said operating mechanism relative tsaid bi-metallic member while the latter remains fixed for the purposeof adiusting the overload oper.. ating characteristics of the switch.

3. In an electric switch, a manually operable operating mechanism,separable contacts engageable and disengageable by said mechanism,overload operating means` including a bi-metallic member holding saidswitch in closed-circuit condition, said bi-metalli'c member moving inresponse to overload condition to release and to cause separation ofsaid contacts, and means to move said operating mechanism relative tosaid bi-metallic member while the latter remains ilxed for the purposeof adjusting the overload operating characteristics of the switch, aninsulating base housing said mechanism and having exteriorly accessibleterminals for making connections to the switch and an adjustment memberaccessible at the front of the base and exteriorly thereof for adjustingthe position of said operating mechanism.

4. In an electric switch, a manually operable operating mechanism,separable contacts engageable and disengageable by said mechanism, abimetallic member engaged by a part oi said mechanism and adapted todisengage said part on overload to cause separation of said contacts,and means to adjust the relativeV positions oi said bi-metal andoperating mechanism by moving said mechanism while said bi-metal retainsits position whereby the overload setting of the switch may be varied.

5. In an electric switch, a manually operable operating mechanism,separable contacts engageable and disengageable by said mechanism, meansbiasing said contacts towards separated position, an overload responsivemember restraining said bias in closed-circuit condition of the switchbut operable to release said mechanism and permit said biasing means toseparate said contacts on overload, and means to move said operatingmechanism relative to said overload responsive member while the latterremains ilxed, for the purpose of adjusting the overload -operatingcharacteristic of the switch. y

6. In an electric switch, separable contacts,

manual operating means, pivotal means operable by said operating means,tripping means having a movable pivoted connection with said pivotalmeans, said pivoted connection moving in response to movements of saidmanual operating means to accomplish contact engagement and separation.

7. In an electric switch, separable contacts, manual operating means,pivotal means operable by said operating means, tripping means having amovable pivoted connection with said pivotal means, said pivotedconnection moving in response to movements of said manual operatingmeans to accomplish contact engagement and separation, and overloadresponsive means normally engaged by said tripping means and arranged torelease said tripping means on overload to accomplish Contactseparation.

8. In an electric switch, separable contacts, manual operating means,pivotal means operable by said operating means, tripping means having amovable pivoted connection with said pivotal means, said pivotedconnection moving in response to movements ci' said manual operatingmeans to accomplish contact .engagement and cause separation, overloadresponsive means normally engaged by said tripping means and arranged torelease said tripping means-on overload to accomplish contactseparation, and means to adjust the position of said tripping meansrelative to said overload responsive means while the latter remainsunmoved.

9. In a switch, a pivoted operator; a rockable member having a springconnection with said operator and being movable in response to movementof said operator, a tripping member pivotally mounted on said rockablemember and movable by said rockable member, separable contacts engagedand separated by movements of said tripping member as said operatorisrnoved, and overload means to release said tripping member to causecontact separation automatically,

l0. In a switch, a pivoted operator, a rockable member having a springconnection with said operator and being movable in response to movementof said operator, a tripping member pivotally mounted on said rockablemember and movable by said rockable member, separable contacts engagedand separated by movements oi' said tripping member as said operator ismoved, overload means to release said tripping member to cause contactseparation automatically and adjustable supporting means for saidrockable member causing movement of the switch mechanism toward or awaytrom said overload means to vary the overload characteristics of theswitch.

11. In a switch, a pivoted operator, a rockable member having a springconnection with said operator and being movable in response to movementoi.' said operator, a tripping member pivotally mounted on said rockablevmember and movable by said rockable member, separable contacts engagedand separated by movements of said tripping member as said operator ismoved, a bi-metal strip engaged by said tripping member and releasingsaid tripping member on overload, and a movable support for moving saidtripping member relative to said bi-metal strip while the latter remainsstationary, whereby variation of the overload setting can be made.

12. In an electric switch, a manually operable operating mechanismincluding spring biasing means, separable contacts engageable anddisengageable upon actuation of said mechanism, said spring meansbiasing said contacts toward open-circuit position from closed-circuitposition, overload operating means operable to cause separation of saidcontacts, said overload means including a current responsive memberrestraining said spring meansv in closed-circuit position of theswitch,'and means to move said operating mechanism relative to saidcurrent responsive member while the latter remains xed for the purposeof adjusting the overload operating characteristics of the switch.

13. In an electric switch, separable contacts, manual operating means,pivotal means operable by said operating means, spring means to causesaid contacts to engage and. disengage, tripping means having a movablepivoted connection with said pivotal means, said pivoted connectionmoving in response to movements of said manual operating means toaccomplish contact engagement and separation.

14. In an electric switch, separable contacts, manual operating means,pivotal means operable by said operating means, spring means to causesaid contacts to ensase and disengage, tripping means having a movablepivoted connection with said pivotal means, said plvoted vconnectionmoving in response to movements of said manual l operating means toaccomplish contact ensasef ment and separation, and overload responsivemeans normally engaged by said tripping means and arranged to releasesaid tripping means on overload to accomplish contact separation.

15. In an electric switch, separable contacts, manual operating means,pivotal means operable by said operating means, spring means to causesaid contacts to engage and disengage, tripping means having a movablepivoted connection with said pivotal means, said pivoted connectionmoving in response to movements of said manual operating means toaccomplish contact engagement and separation, and overload responsivemeans normally engaged by said tripping means and arranged to releasesaid tripping means on overload to accomplish contact separation, andmeans to adjust the position of said .tripping means relative to saidoverload responsive means while the latter remains unmoved.

DAVID W. JOHNSON.

REFERENCES CITED The following references are ot record in the ille ofthis patent:

FOREIGN PATENTS Country Date British Aug. 20. 1934 Number

